________________________________________ From: Greg Freemyer [greg.freemyer@xxxxxxxxx] Sent: Thursday, July 23, 2009 2:31 PM To: Bill Weiler Cc: Kernelnewbies Subject: Re: Drive tester On Wed, Jul 22, 2009 at 7:55 PM, Bill Weiler<weilerb@xxxxxxxxxxx> wrote: > I wanted to make an Application that could send scripted SCSI and SATA > commands to my drives. I have found my Fedora Linux to be too complex to > control the drives in this way. I have looked at minimal Linux but I think > this would have the same problem. Is there an easier Open Source OS, or an > embedded PC Linux that would be easier to modify? Bill, For sata drives, have you looked at the SG_IO interface? That is how hdparm interfaces with the kernel. I know it sends a lot of low level ATA commands to the drive from user space. I think most use the SG_IO interface. How much simpler can it get? strace hdparm may give you an education as to how simple it is. fyi: I believe the kernel looks for dangerous ata commands and blocks them. But I think those are the types of commands that cause data loss. Not sure what the criteria is. I have studied hdparm and the SG_IO interface and delved into the scsi drivers and ata drivers. For example, I wanted to script a single NCQ and a single NCQ write. A normal read(fd,buf,4096) does 1 NCQ read but a write(fd,buf,4096) does dozens of NCQ reads before doing the 1 NCQ write. How do I get rid of these reads? Also, I need to do soft and hard resets and these are not exposed. Greg -- Greg Freemyer Head of EDD Tape Extraction and Processing team Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer Preservation and Forensic processing of Exchange Repositories White Paper - <http://www.norcrossgroup.com/forms/whitepapers/tng_whitepaper_fpe.html> The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
